The present invention relates to a record book or pad and is primarily concerned with such a book or pad for duplicating in which a copy of an impression or marking, such as a message, applied by pressure on one sheet is formed on an adjacent underlying sheet, typically to provide a record of the marking if one of the aforementioned overlying sheets is removed from the book or pad following use. Books or pads having record sheets and removable sheets in overlying relationship and which are disposed alternately to provide pairs each with one record sheet and one removable sheet are well known. An example is a telephone message book where a manuscript note of a telephone conversation is applied to an upper removable sheet of a pair for that note to be reproduced or duplicated on the underlying record sheet of the pair following which the removable sheet is removed, usually by tearing along a line of weakness on that sheet while a record of the message is retained in the book.
To provide the transfer of the marking from the record sheet to the removable sheet (or vice versa), a sheet of carbon paper was conventionally inserted between the two sheets in well known manner. However, it is now widely considered that the use of carbon paper for the aforementioned purpose is obsolete and so-called carbonless paper is preferred in which a face of a duplicating sheet is coated in a manner known in the art with a duplicating material which responds to pressure from a mark or impression applied thereto through an overlying sheet so that a copy of that mark is reproduced on the appropriately coated face of the underlying duplicating sheet. Generally, and simplistically, the known coating for a duplicating sheet comprises minute capsules or bubbles which break or burst (in response to the localised pressure applied through an overlying sheet and created by the aforementioned marking on the overlying sheet) causing an agent to be released which develops the copy of the marking.
One known form of duplicating book or pad using carbonless paper has its sheets collated in pairs, each pair consisting of a top sheet and an adjacent underlying duplicating sheet. Each of these sheets has its face which abuts and opposes the adjacent face of the sheet in its pair, coated with the aforementioned duplicating material and when a mark or impression is applied to the top sheet for localised pressure from the marking to be transferred through that top sheet onto the underlying duplicating sheet, capsules burst in the respective coatings on the abutting faces between the sheets in the pair causing respective agents to be released and these agents inter-react to develop a copy of the applied marking on the face of the duplicating sheet. The present invention is primarily concerned with duplicating books or pads of this general form where it is essential that appropriate coatings are applied to each of the opposing faces of the top sheet and duplicating sheet in a pair before a mark or impression applied to the top sheet will, be duplicated on the underlying duplicating sheet - this is considered advantageous to alleviate the possibility of confusing copy markings inadvertantly being developed on the coated face of the duplicating sheet through an uncoated overlying top sheet (which is known to occur with another form of carbonless paper known in the art as "action paper").
In the interests of the conservation of the environment there is an ever increasing demand to reduce the consumption of paper and in the stationery industry there is a need to maximise the efficient usage of paper to achieve cost effective manufacture of every day stationery products such as duplicating books or pads of the kind generally discussed above. It is an object of the present invention to provide such a book or pad which lends itself to achieving the aforementioned aims.